Telephone subscribers can own their own equipment and connect such equipment to the incoming telephone line of a telephone service provider at a terminal typically connected to the side of the subscriber's dwelling or place of business, hereinafter referred to as the "subscriber building." Thus, the terminal includes a "demarcation point" that is the connection point between the equipment that is accessible to the subscriber (the "subscriber equipment") and equipment that is accessible only to the service provider (the "service provider equipment"). The demarcation point is helpful in fault detection and isolation by easily allowing for the determination of whether a fault exists in the service provider equipment or the subscriber equipment.
Typically, this demarcation point is provided by a telephone network interface device (NID). A conventional NID is housed within a cabinet, typically called a building entrance terminal (BET), having both a service provider compartment and a subscriber compartment for mounting the service provider's and subscriber's equipment, respectively. These separate compartments are accessible through separate doors or covers. This permits the subscriber to have access to the subscriber's equipment to allow the subscriber to test the telephone line at the demarcation point. However, the subscriber does not have access to the service provider compartment.
Typically, NIDs provide a telephone jack for connection to the incoming telephone line from the service provider and a telephone plug for connection to the subscriber telephone line. When the plug is inserted into the jack, a telephone connected to the subscriber telephone line is rendered operable. Should the telephone become inoperable, the telephone plug can be unplugged from the telephone jack, thus providing a demarcation point to permit the plug of an operating telephone to be plugged into the jack to facilitate the determination of whether the fault exists in the service provider equipment or in the subscriber equipment.
Most NIDs accept a relatively small number of incoming telephone lines that are connected to a matching number of subscriber telephone lines. However, typical telephone network systems serve a large variety of subscribers in office buildings, apartment complexes, and the like where it is necessary to connect many incoming telephone lines to many subscriber telephone lines.
Existing BETs do not provide for connections to many different subscriber lines while at the same time making access to the subscriber and service provider compartments easy and convenient. Existing BETs typically provide subscriber and service provider equipment side-by-side on the same surface of a fixed plate. This requires a large amount of surface area on which to mount all of the subscriber and service provider equipment, thus necessitating a large plate in the terminal cabinet. Also, existing BETs that mount service provider equipment on the same surface as subscriber equipment provide for an environmental seal by providing a separate sealed cover for the equipment. A separate cover, of course, is an additional piece that must be opened and closed each time the equipment is accessed, thus making servicing of the equipment more complicated. Furthermore, when multiple BETs are stacked on top of one another when the number of subscriber lines is very large, the number of subscriber lines exiting the BETs is very large and hard to manage. Existing BETs do not provide for an external routing channel in which to route subscriber wires exiting the terminal cabinet.
Therefore, there is a need in the art for a BET that provides for connections to many subscriber lines using a small, compact cabinet such that access to both the subscriber and service provider equipment is quick, simple, and convenient.